<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 800px;
            height: 340px;
            position: relative;
            border: 2px solid skyblue;
            background-color: skyblue;
        }
        .box1{
            position: absolute;
            width: 70px;
            height: 70px;
            animation: box1 5s infinite;
        }
        @keyframes box1{
            0%{
                width: 50px;
                height: 50px;
                border-radius: 50%;
                background-color: pink;
                top: 100px;
                left: 40px;
            }
            25%{
                width: 30px;
                height: 30px;
                border-radius: 50%;
                background-color: pink;
                top: 10px;
                left: 100px;
            }
            75%{
                width: 40px;
                height: 40px;
                border-radius: 50%;
                background-color: pink;
                top: 250px;
                left: 380px;
            }100%{
                width: 100px;
                height: 100px;
                border-radius: 50%;
                background-color: pink;
                top: 30px;
                left: 510px;
            }
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="box1"></div>
    </div>
</body>
</html>